<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>btn</title>
  <link rel="stylesheet" href="btn.css">
</head>
<body>
  <button class="my-btn">按钮</button>
  <button class="my-btn my-btn-primary">按钮</button>
  <div class="my-btn-group">
    <button class="my-btn">按钮</button>
    <button class="my-btn">按钮</button>
    <button class="my-btn">按钮</button>
  </div>
</body>
</html>